Molecular weight determining from

Hven fractionated polymer samples are generally polydisperse, which means that the molecular weight determined from intrinsic viscosity experiments is an average value. The average obtained is the viscosity average as defined by Eqs. (1.20) and (2.40) as seen by the following argument ... 

Number-average molecular weights determined from GPC and H NMR. Estimated from H NMR. 

For high-molecular-weight materials, an electrospray spectrum provides a number of independent molecular weight determinations from a single spectrum and thus increased precision. 

Equation (44) shows the average molecular weight determined from osmometry to be the number average molecular weight as defined by Equation (1.14). 

The number-average molecular weights determined from the gel permeation chromatograms showed an average deviation of 7% relative to the osmo-... 

In electrospray ionization, compounds with a mass in excess of 500 Da may be prone to the formation of multiple-charge ions, either in positive-ion or in negative-ion mode [22-23], The averaging algorithm [23-24] can be used for molecular-weight determination from an ion envelope of multiple-charge ions (Ch. 16.2.2). Various automated computer-based procedures for the deconvolution or transformation of the electrospray mass spectra of proteins have been introduced. 

Fig. 9.— Double Log Plots of (a) Intrinsic Viscosity, (b) the Reciprocal of the Diffiision Coefficient, and (c) Sedimentation Coefficient Data versus Molecular Weight for Human Cervical Mucins. [Key and O, whole mucins and , subunits and A, T-domains. Molecular weights determined from Zimm plots (filled symbols) or the Svedbeig equation using QLS (open symbols). Values for the slopes are in all cases consistent with a random-coil model and not with a rigid sphere or a rod.]...

Problem 4.8 Show that the molecular weight determined from osmotic pressure measurements is the number average molecular weight. 

Figure 4.5 Molecular weight determination from osmotic head (/i) and concentration (c) data (Problem 4.9).

The molecular weight obtained by application of Eq. (4.94) to a polydis-perse polymer will be some average over the molecular weight distribution characteristic of the polymer. It can be easily shown tl the molecular weight determined from light scattering measurement is Mw... 

Materials. Three samples of poly-7-benzyl-L-glutamate were studied. Polymer I was obtained by polymerizing 7-benzyl A-carboxy-L-glutamate anhydride by sodium methoxide in DMF and polymer II by a similar polymerization using n-hexylamine as initiator. Both were purified by reprecipitation. The molecular weights determined from the viscosity-molecular weight ratio of Doty et al. (4) were 67,000 for polymer I and 21,000 for polymer II. Polymer III was a commercial sample (Pilot Chemical Co.) of molecular weight 275,000. All solvents were purified by standard laboratory procedures. 

Molecular weight determined from the impulse number of the precipitated polyester according to... 

Harmon, J., et al. (1985). Molecular Weight Determinations from Radiation Inactivation, Methods Enzymol. 117 65-94. 

MOLECULAR WEIGHT DETERMINATION FROM OSMOTIC PRESSURE... 

Table 1 Molecular Weights determined from GPC analysis for selected CRPPs... 

Figure 4 Molecular weights determined from peaks observed Figure 5 (a) Ru04-stained SEM from an unnanealed in DCM and HFIP chromatograms from PC/PET samples PC/PET blend (b) annealed in the melt for 60 minutes...

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